1. Field
Embodiments of the present invention relate to a check valve of a hydraulic brake system having a simplified configuration to ensure easy processing and assembly.
2. Description of the Related Art
A vehicle is essentially provided with a brake system for braking. Recently, a variety of brake systems to achieve stronger and stabilized brake force has been proposed. Examples of brake systems include an Anti-lock Brake System (ABS) that prevents wheel slip during braking, a Brake Traction Control System (BTCS) that prevents sudden unintended acceleration of a vehicle or slip of driving wheels upon sudden acceleration, and a Vehicle Dynamic Control System (VDCS) that is a combination of an ABS and BTCS and stably maintains traveling of a vehicle by controlling brake oil pressure.
Such an electronically controlled brake system includes a plurality of solenoid valves to control hydraulic brake pressure transmitted to hydraulic brakes mounted to wheels of a vehicle, a pair of low-pressure and high-pressure accumulators in which oil discharged from the hydraulic brakes is temporarily stored, a motor and pump to forcibly pump the oil of the low-pressure accumulator, a plurality of check valves to prevent backflow of oil, and an Electronic Control Unit (ECU) to control operations of the solenoid valves and motor. These components are accommodated in a compact aluminum hydraulic block.
FIG. 1 is a sectional view illustrating a check valve used in a conventional electronically controlled brake system. In one example, a check valve, which is installed in a path between a suction side of a pump and a low-pressure accumulator, functions to prevent oil of a master cylinder from being transmitted to the low-pressure accumulator and also, to prevent oil of a wheel cylinder from entering the suction side of the pump when a motor is driven to operate the pump.
As illustrated, a check valve 1 includes a valve housing 3 press-fitted into a hydraulic block 2 having an oil path 2a, a ball 4 accommodated in the valve housing 3 to open or close an oil passage 3a defined in the valve housing 3, a spring 5 to elastically support the ball 4 toward the oil passage 3a, and a spring seat 6 assembled into the valve housing 3 to guide the spring 5.
The above-described conventional check valve 1, however, has a complicated external appearance and is difficult to assemble because only functionality is considered upon manufacture thereof. In particular, the valve housing 3 having a complicated shape as illustrated causes a large product size and expensive manufacturing costs because it is manufactured only by cutting. In addition, since the spring seat 6 is press-fitted only into the valve housing 3, assembly reliability is deteriorated after long-term use.